HARRISBURG — Mitt Romney got the next best thing Friday to an endorsement from U.S. Sen. Pat Toomey, he got validation.

"I think Mitt Romney is a conservative and if he's president, he'll govern as a conservative," Toomey, R-Pa., told reporters after a speech to the Pennsylvania Leadership Conference, the annual gathering of conservatives in the state.

Toomey made his mark in Washington hunting down and replacing Republican moderates in Congress with Republican conservatives as president of Club for Growth, a powerful anti-tax group.

A tea party kingmaker, U.S. Sen. Jim DeMint, R-S.C., also affirmed Romney's conservatism after meeting with him Thursday on Capitol Hill. DeMint, like Toomey, came just short of endorsing Romney, who is seeking the Republican presidential nomination against Newt Gingrich, Rep. Ron Paul and Rick Santorum.

"I'm not only comfortable with Romney," DeMint said Thursday, "I'm excited about the possibility of him possibly being our nominee."

Toomey focused his 30-minute remarks on capitalism and the merits of a free market, arguing that Bill Gates will do more for humanity through his work developing Microsoft than through his philanthropy.

In a brief news conference afterward, the discussion centered on politics.

Toomey reiterated he is not endorsing anyone in the Republican presidential primary, which will be held April 24, and brushed off suggestions that he's on the list of potential running mates.

"I think that is so extremely unlikely that I don't spend any time thinking about it," he said.

When it was pointed out that he said something similar ahead of his appointment to last year's congressional supercommittee tasked with reducing the federal deficit, he quipped, "It shows that I can be wrong."

While Toomey is not formally endorsing a candidate, he quite clearly would be happy with a Romney nomination.

When asked about the social issues that have permeated the primary debate, issues closely aligned with Santorum, the former U.S. senator from Pennsylvania, Toomey said the campaign trail conversation has to be about the economy.

When asked for evidence of Romney's conservative credentials in light of his Massachusetts health care plan that some call the blueprint for Obama's reform law, Toomey said Romney "is absolutely committed to the principles of limited government and free enterprise."

"I think he knows the free enterprise system is the source of prosperity and opportunity and personal fulfillment and elevating people out of poverty," Toomey said. "He's been a practitioner, so he understands from a very concrete sense how markets work and create opportunities."

Romney foes Santorum and Gingrich have peeled away primary voters by highlighting Romney's more moderate stances when he was governor of Massachusetts. This week they pounced on a comment from a Romney campaign aide that the campaign was like an Etch-a-Sketch and — just like the children's toy — the slate can be reset with the flick of a wrist.

Santorum and Gingrich said it was evidence that Romney would shift back to the political center for the general election.

South Carolina Republican Gov. Nikki Haley, who spoke at the conference on behalf of Romney, also vouched for Romney's conservative bona fides, saying that Romney promised her he would repeal Obama's health care law on Day 1 because he believes in states' rights.

"Is he a flip-flopper? Ultimately that's going to be up to you," she told the audience. "What I care about is the issues. He's absolutely pro-life, he's absolutely going to repeal health care, he's absolutely pro-military, he absolutely is a business person. … Those are the things I want to know."

Santorum and Gingrich are scheduled to speak to the conference Saturday.